Internal Memory Space in Ray Vs Neo V

Just curious over this aspect. The internal storage in Xperia Ray borders on 230 MB, while it's approx 270 MB on the Xperia Neo V

[Settings -> Storage -> Internal storage (Available space)]

I uninstalled all the apps on both the phones save for Opera Mini (the lighter version) and Twitter and all the preinstalled apps have been updated to the latest version in the Android Market (Apps from Google/Sony Ericsson etc.). What could be the reason for this difference, since both these phones have more or less the same features except for the camera/HDMI?